1. Field of the Invention
The present invention relates to a method of printing bar codes on pieces to deliver, such as mail pieces, and a method of reading bar codes printed on pieces to deliver, which help enhance efficiency of delivering the pieces. The invention also relates to a method and system for encoding and decoding bar codes, which are fit for use in bar-code encoding/decoding system designed to increase the efficiency of delivering pieces.
2. Description of the Related Art
In Japan a postal zoning system has long been adopted to enhance mail-delivering efficiency. In the postal code system, a sender writes on the mail piece (i.e., the letter) a postal code. The postal code consists of either three figures or five figures, designating the zone in which the receiver lives. The sender mails the mail piece, which is transported to the nearest post office, along with other mail pieces. In the post office, the postal codes written on the mail pieces are optically read. The mail pieces are sorted in accordance with the codes thus read, more efficiently than otherwise.
Recently, a new postal zoning system has been proposed in which the conventional postal code be replaced by a novel postal code consists of seven figures. The sender writes on a mail piece the novel postal code designating the receiver's town and the address number designating the receiver's lot number. In the central post office, an optical character reader (OCR) reads the postal code and address number written on the mail piece, both codes thus read are converted into a bar code, and the bar code is printed by a bar-code printer on the mail piece, i.e., an envelope or a post card. The mail piece with the bar code printed on it is sent to the local post office. In the local post office, a bar code reader reads the bar code on the mail piece and outputs the data representing the postal code and address number. In accordance with this data, the mail piece is sorted automatically, thereby increasing mail-delivering efficiency even more.
It is proposed that a so-called "VCS (Video Coding System)" be used if the OCR fails to read the bar code (i.e., novel postal code and address number). The VCS prints a bar code on the mail piece, which represents an ID number indicating the date of reading the bar code, the serial number of the bar-code printer and the lot number for the mail piece. The image data of any mail piece on which the ID number is printed is displayed to an operator. The operator reads the postal code and the address number written on the mail piece and inputs both codes, which are converted into a bar code.
The bar code representing the postal and address codes and the bar code representing the ID number are printed at a prescribed position on that side of the mail piece on which the sender has written the receiver's name and address. The bar codes may overlap the receiver's name or address, because the sender can write the receiver's name and address at any position he or she choose on said side of the mail piece. In this case, the bar codes are not read at all or read incorrectly. If the bar codes are not read at all, the receiver's name and address written by the sender must be read and input by the operator, making it difficult to increase the mail-delivering efficiency and inevitably increase the cost of delivering mail. If the bar code are read but incorrectly, the mail piece will be delivered to a wrong person and be eventually reach the receiver much later.
The bar code representing the ID number can be far smaller than the bar code representing the postal and address codes, and is less likely to overlap the receiver's name or address than the bar code representing the postal and address codes. Hence, the probability that it is not read at all or is read incorrectly is low. Nonetheless, it may not be read at all or may be read incorrectly, just like the bar code which represents the postal and address codes.
As indicated above, the bar code printed on a mail piece, which represents the destination data (e.g., a postal code and an address number), is not read at all or is read but incorrectly if it overlaps the receiver's name or address written on the mail piece. As a consequence, the receiver's name and address must be read and input by the operator, which inevitably reduce the mail-delivering efficiency, or the mail piece is delivered to a wrong person.
Representing the destination data, the bar code printed on a mail piece does indeed helps to improve mail-delivering efficiency. If the bar code cannot be read or is read but incorrectly, however, the operator needs to pick out the mail piece so that a postman may return the mail piece to the sender. Inevitably, the efficiency of returning mail pieces to the senders cannot be raised.
Accordingly a first object of the invention is to provide a method of printing bar codes on mail pieces such that address-unknown pieces can be automatically picked out, thereby to enhance the efficiency of returning the mail pieces to the senders.
A second object of the present invention is to provide a method of printing bar codes on mail pieces, which can increase the reliability of the bar codes which represent destination data items.
A third object of the invention is to provide a method and system which can encode and decode bar codes representing numerical data such as ID numbers, with high reliability.